Electric cable connector



Feb. 26, 1952 D. BERGAN ELECTRIC CABLE CONNECTOR 2 SHEETSSHEET 1 Filed April 8. 1947 INVENTOR. We??? 0. 547F634 HTTO/PNEV Pilxrl ll Feb. 26, 1952 BERGAN 2,587,095

ELECTRIC CABLE CONNECTOR Filed April 8, 1947 2 SHEETS-SHEET 2 E II l ll III/IIIII/II/I/I/l/III/I/IA 7f wow Patented Feb. 26, 192

UNITED STATES PATENT OFFICE ELECTRIC CABLE CONNECTOR Martin D. Bergan, Westfield, N..J., assignor to The Thomas & Betts 00., Elizabeth, N. J., a corporation of New Jersey Application April 8, 1947, Serial No. 140,111

' Claims. (01. 287109) metal, and the tube or sleeve compressed, crimped' or otherwise deformed onto the conductors, usually with one or more crimps impressed on the tube and therethrough onto the portions of the tubes engaging the ends of each conductor. It is further suggested in the prior art that the bores of such coupling tubes be roughened, sometimes threaded or knurled or otherwise serrated, in order to enhance the gripping effect between the tube or sleeve and the strands which form the coupled connectors. In practicing the known methods of forming such connectors, it not infrequently occurs that the more or less fine wire strands which make up the conductors are broken or otherwise damaged, with a resulting reduction in tensile strength of the conductors particularly in those portions thereof which are within, and often also in those protruding portions which are immediately adjacent, the ends of the coupling sleeve.

The primary object of the invention is to provide an improved technique in the forming of such connectors so as to couple a pair of cables in such way as will maintain intact the tensile strength of the conductors, both in the region within and in the region adjacent the ends of the couplings, and at the same time to provide for a more positive connection between the conductors and the coupling sleeve than has been possible heretofore; and also to minimize the possibility of breaking the wires of the conductors, which under some conditions may be fine wires, either during the crimping operation or later when the devic is in service.

Broadly, this objective is obtained by a refinement in the usual sequence of crimping operations in that an outwardly progressive, step-bystep sequence of crimping or compression actions is had in spaced apart relation on the portion of a preformed stock tube encasfng each conductor, operating either first on one side and then the other side of the center of the tube, that is, on the portion of the tube enclosing the end of one conductor and then on the portion enclosing the end of the other conductor, or

' starting at the portion of the tube containing stock tube from its initial circular in cross sec- 7 the end of one tube and progressively crimping each half of the tube before crimping the other half. More specifically defined, the invention features an outwardly successive deforming at two or more places of each half of a cylindrical tion shape into a hexagon in cross section shape, beginning first near one end of each conductor therein so as to give the intruded end portion of each conductor an innermost constricted, waist or-hour-glass design of rounded double conical form while permitting the balance of each tube so acted upon to slide freely outwardly without restraint on the conductor or cable. Then, in spaced relation to the first crimp so made each half of the tube is subjected to a second crimp-' ing or deforming operation in the area in each case towards the adjacent end of the tube and thus in each of the areas so previously free to readjust itself on its associated conductor. The re-' sult of this second deforming operation is to provide a second or next outer waist or hour-glass form of constriction to the bore of the tube and to the portion of the conductor so encircled by the portion of the tube thus involved in this second crimping operation. Likewise the tube in the illustration showing is subiected finally to an outermost or third crimping operation at each end.

In this way the intruded end of each conductor is held by the resulting coupling sleeve by at least two, and as shown preferably three, longitudinally spaced apart areas of constriction, each of which gradually increases in cross section, and in each case forms a transverse plane of maximum compression gradually enlarging to a pair of transverse planes of little or no compression on opposite sides of each region of maximum compression.

For the purpose of minimizing any tendency of the tube to resist a desired automatic readjustment oi the parts thereof in the distention of the same lengthwise incidental to such radial distortion, the present disclosure features the omission of any corrugations or roughening of the extreme end portions of the bore of the stock tube and the forming of the end portions of the bore smooth and thus free of any restraint on the shifting of the conductors in the uncrimped areas.

In some situations couplings of the type herein featured are subjected to vibration which tends to cause the coupling sleeve to shear or at least mar the surface of the conductors particularly in the regions adjacent the places where they extend out of coupling sleeves.

Accordingly, another object of the invention is to provide such form of stock tube which, when distorted as herein provided, will provide a clearance between the ends of the bore and the portions of the conductors encircled thereby so as to permit at least a limited freedom of relativ transverse movement.

The present disclosure is particularly intended to be used on electric power lines strung on transmission towers .or other outside poles and other equipment exposed to low temperature weather conditions, and thus subject to an accumulation of ice. forming on the cables and on their connectors. It is suggested that the lines be de-iced by passing current of relatively high amperage through the lines for short periods of time. This, of course, raises the temperature of the lines and the duration of such treatment is gauged experimentally to effect a melting of the ice. In general practice the connectors usually become hotter than the balance of the line, with resulting undue expansion of the connectors, a loosening of the connection between the cables or conductors and the connectors and other undesirable results occur when known forms of connectors are used.

Accordingly, another object of the invention is to provide a coupling of the cables in such way that the resistance imposed on the line by the passage therethrough of such high amperage deicing current will avoid the objection of unduly heating the connectors and at the same time obtain a quick and economic defrosting of the system whenever necessary without deleterious action on the system.

Still another object of the invention particularly designed for use in the coupling of cables which include the usual steel cores and featuring a desire to minimize in the amount of material necessary to couple the cables, is to dispose a pair of such connectors in telescoped relation with a relatively small connector for connecting the steel cores contained within a relatively large connector connecting the cables.

Various other objects and advantages of the invention will be in part obvious from a consideration of the method features of the dis closure and from an inspection of the accompanying drawings and in part will be more fully set forth in the following particular description of one method of practicing the invention, and the invention also consists in certain new and novel modifications of the preferred method and other features of construction and combination of parts hereinafter set forth and claimed.

In the accompanying drawings:

Fig. 1 is a plan view of the right hand portion of a stock tube from which a preferred form of the coupling sleeve aspect of the invention may be formed;

Fig. 2 is a longitudinal sectional view taken on the axis of the stock tube and taken on the line 2-2 of Fig. 1;

Fig. 3 is a view in side elevation of a preferred embodiment of the invention illustrating the right hand end of the finished product obtained from following the crimping method herein disclosed when using the complete stock tube, a portion of which is shown in Figs. 1 and 2;

Fig. 4 is a longitudinal sectional view taken axially of so much of the completed article as is shown in Fig. 3 and taken on the line 4-4 of Fig. 3;

Fig. 5 is a transverse sectional view and shows in full lines, and in the center thereof, a transverse section of the finished coupling of Figs. 3 and 4 taken on any of the transverse sections of greatest compression, such as on the line 5-4 of Fig. 3; and also showing in dotted lines the squeezing die elements of a conventional diepress for crimping the tubes forming the finished connector;

Fig. 6 is a view in transverse section of the coupling tube taken on the medial transverse plane of the stock tube and taken on the line 6-6 of Fig. 1;

Fig. 7 is an axial sectional view of a complete assembly of coupled cables corresponding to the partial showing of Fig. 4 and in which the steel cores C are coupled together by a small sleeve similar to the larger sleeve used for coupling the cables and;

Figs. 8 and 9 illustrate another embodiment of the invention used as a dead-end coupling for connecting cables at least one of which is of the steel core type.

Fig. 8 is a view in axial cross section of a dead-end coupling with the anchor element having the steel core intruded into the same and the cable loose in a companion element before either its associated cable or its core is crimped in place and;

Fig. 9 is a view partly in side elevation and partly in section of the completed coupling with both cables and a steel core of one anchored in place.

Referring first to the stock tube ID in Figs. 1 and 2 as supplied by the tube manufacturer, it will be understood that it is an open end tube about eight inches long and having a bore extending axially therethrough. The tube exteriorly is of cylindrical form except at its ends where it is slightly tapered to provide a frustoconical exterior end surface 28' of least cross section of material. In the specific form of the device illustrated this tube is formed of a commercial grade of wrought aluminum. The midportion ll of the bore is of cylindrical form, of uniform cross section throughout and is serrated or roughened to provide an increase in area of its gripping surface. The serrations are formed by means of a V-thread H of small pitch, preferably about thirty-two to the inch and tapped into the midportion after the stock tube is otherwise formed. In one form of the disclosure the threads have a depth of between .010 and .040 inches. The tube has a looking-glass symmetry relative to a medial transverse plane indicated by the medial section line 6-6, so that the detailed description of either half of the tube on one side of the line will be sufficient for the other half with obvious reverses in location of the corresponding parts.

The extreme outer ends of the bore of the stock tube as shown in section at its right end l3 in Fig. 2 has a diameter slightly greater than that of the bore at its threaded mid-portion II and is of uniform cross section. The intermediate portions of the bore adjacent opposite ends thereof, that is, between the midportion H of less diameter and the ends l3 of enlarged diameter is bevelled so that these portions each defines a frustum of a cone with its larger end facing outwardly. The cross section of material of the stock tube I0 is greatest within the length of the midportion H; is of least cross section in the cylindrical end rings I5 outlining the outer ends of the bore of maximum diameter assaoas e and gradually increases in cross section in th band I which encircles the frusto-bonical bore portion II. The threads i2 gradually disappear within the length of bore portion M which defines the band It.

The midportion of the tube in the transverse medial plane 6-6 is provided as best shown in Fig. 6 with four eircumferentially spaced apart center stops I1, and on one side thereof with a transversely extending hole 18 opening into the midportion of the bore II. This hole is for the purpose of inserting a rust preventive filler into the bore in the space 23 formed between the adjacent ends of the conductors in those cases where such fillers are indicated.

The stops are formed preferably by subjecting the tube to the action of a die press organized with four inwardly moving indentors to indent or deform the tube at four equi-distantly spaced points to form depressions IS in the outside face of the wall of the tube and which depressions will cause the inner wall of the tube to bend inwardly and thus form the center stops l1 projecting into the bore of the tube as shown in Fig. 6.

It will be understood that the stock tube it being made of aluminum will at all times possess a thin film of aluminum oxide, too thin to be shown, as a skin coating on all exposed surfaces, including the thread II, as more fully disclosed in my co-pending application, Serial No. 618,218, filed September 24, 1945, now Patent No. 2,480,280 dated August 30, 1949. i

The invention is disclosed in connection with the use of the tube as a jumper splicer for connecting two cables, wire or other electric conductors and two such cables or conductors are shown at A and B in Fig. 4.

The cables as illustrated include at their centers a steel reinforcing core C either a single conductor or stranded wire wrapped spirally about I .which are a plurality of aluminum twisted strands D forming the conductors of the cables. These cables each has a diameter slightly less than the diameter of the threaded midportion of the bore so that they can be slid freely into position through opposite ends of the tube. As shown at the right of Fig. 4 the exposed ends of the cable conductors have a diameter slightly less than that of the outer ends i3 of the bore so that there is provided at all times an annular clearance 20--therebetween permitting freedom of relative transverse movement between the cables and the coupling sleeve at the open ends of the sleeve as may be caused by the oscillation of the connector or cables.

In operation and assuming the ends of the conductors A and B to be intruded into the tube, until they engage the stops I'I, each half of the tube adjacent its midlength at 6-5 is then subjected to a crimping operation to deform the areas so crimped from their initial configuration, circular in cross section, into the hexagonal form shown in cross section in Fig. 5. Preferably the dies are caused to act under a squeeze force sufficient to constrict the tube and with it the portion of the conductors within the tube areas so constricted to cause the cross sectional area to approach closely the aggregate cross sectional area of the metal strands D and steel core C. This operation is performed by inserting for each conductor first an innermost portion of the tube l0, and then an outer portion of the tube successively between the die elements E and F of a die press as suggested in ghost outline in Fig. 5. and following somewhat conventional cold flow crimping practices in this respect.

The die elements are each provided in its work face with a concaved recess G. The work faces are designed for engaging oposite sides of the tube and are identical. Each recess is outlined on opposite sides by a pair of pressure faces H and I, each extending at an angle of thirty degrees to the line of thrust l-t of the dies as they approach each other to give the desired hexagonal form in cross section to each crimp. As the diesapproach each other as indicated by the arrows the two inclined pressure faces H and 1, top and bottom, will first engage the tube I 0 at the four upstanding sides before the bottoms J of the twov recesses engage the top and bottom of the tube. This preliminary distortion causes the tube It at the place so engaged, as well as the portion of the conductor therein, to assume a somewhat fat elliptical form, with its major axis extending vertically in the direction of the line l-t of the Fig. 5 showing. At the termination of the squeeze action of the die press and when the die elements almost meet, the cross section has changed gradually and progressively from such intermediate elliptical forminto the final external hexagonal form shown in Fig. 5 and the cables resume a form circular in cross section.

During this change in configuration the wire strands D tend to slide one on to the other to scrape off any oxide coating which may have formed thereon and to form eventually a metalto-metal contact between the connector sleeve and the two cables A and B. The serrated surface H as it creeps on the external strands also tends to scrape off any oxide coating both on the bore wall and on the strands with the result that a more perfect and clean electric contact is provided between each conductor and the coupling sleeve than has been possible heretofore.

The method distinguishes from known practices particularly in the manner in which the seouence of crimping actions is performed. The first crimping operation is performed preferably first on one and then on the other areas encircling the portions of the conductors nearest the medial plane 6-8. For instance, the first operation is a distorting of the tube inwardly along the four radial lines, as indicated, that is, along two pairs of opposing squeeze pressure lines as indicated by the dotted arrows marked i" to form the first crimp l. The second crimping operation is at the point indicated by the cross section line 5-5 to form the second crimp. It is noted that in both of these cases the associated conductor or cable A or B, as the case may be, is engaged by the tube and thus squeezed in spaced relation to its adjacent end and that each end of each conductor takes the gradually constricted or hour-glass form indicated at 2|. The

extreme inner ends 22 of the conductors are not constricted and on the contrary are caused to fiare outwardly, so that these extreme ends are of greater diameter even than the uncompressed part of the conductors. The strands D tend to elongate or untwist in both axial directions, bulging in one way slightly into the open space or clearance 23 formed between the adjacent ends of the cables, but more extensively outwardly, that is,-away from the line 6-6. This outward distention of both the tube and conductor is indicated by the single headed and relatively short arrows shown at the top center of Fig. 3. The steel core C does not resist any creeping of the wire strands on the same, as the strands tend to readjust themselves during the crimping operation herein featured.

Several actions take place as the result of the squeezing together of the strands D in forming the two-hour-glass configurations sometimes hereinafter referred to as conical wedging keys operalive to resist any bodily axial separating movement between the tube and conductor. Considering either cable or conductor the strands D thereof tend to approach parallel relation and this brings the strands closer together and incidentally causes the strands at the interior of the conductor to scrape one on the other thus providing a more positive electric contact between the strands than was present therein before the end portions of the conductors were so compressed. It will also be understood that the outer faces of each conductor D have their initially adhering oxide coating scraped off by the threads I2 as these threads become increasingly spaced apart, increase their pitch and become deformed and bite into the oxide coating as is more fully described in my above identified co-pending application.

After the two inner crimps I and 2 have been made as thus described, another pair of crimps, one of each side of the plane 6-6 is made in outwardly spaced relation to the next adjacent and previously formed inner crimps 2|. In order to save space on the drawing only one of this second pair of crimps is shown and marked 3 or 4 depending on which comes next in the order of crimping. It is appreciated that both of this second pair of crimps are made in the area of the tube which has been .just previously shifted outwardly by reason of the formation of its asso ciated first and second crimps. The crimps 3 or 4 then form on each side a second constricted hour-glass or waist-like portion 2|, so that the two waists 2i and 24 on each side of the plane 6-6 form an undulated configuration of alternately constricted and un-constricted areas located between the extreme inner end of the conductor and the portion thereof which emerges from the tube at the intermediate portion H of the bore. While the areas 25 of the conductors within the uncrimped portions 26 of the tube are thus referred to as unconstricted areas, as a matter of fact, the areas 25 become expanded at least slightly from their initial configurations and thus take up the initial clearance between the cables and the original bore of the tube. The axial distention of the tube in the region of the second crimp 3 or 4 is again more extensive in the outer than in the inner direction and, accordingly, the difference in axial distention has been indicated at the top of Fig. 3 by a double headed arrow with the larger head pointing outwardly, that is, toward the right and in the direction of the greater distention.

In the same way a pair of outermost crimps are formed near the end of the tube. One of these crimps is indicated at and similarly constriets the conductor B to form another and outer hour-glass constriction at 21.

The outer crimps 21 are of a less degree of compression than is present in the crimps I, 2, 3, 4. As the difference in constriction is slight no attempt has been made to show any difference in the crimps of Figs. 3 and 4.

While only three such crimpings are shown to the right of the plane 5-4 in Fig. 1, and one crimping shown to the left of this plane, it will be understood that in actual practice any num- 8 her of crimps will be utilized as may be required by the size of the cables and by the size of the coupling connection to be made. In so forming the outermost crimps 5, the extreme end of the coupling sleeve distends to form a trumpet-like outwardly flared end 28 which tends to increase the clearance 20 radially into a funnel-like form. This has the effect of curving the taper at the end of the sleeve bore and gradually constricts each cable as it enters the sleeve so that the amplitude of vibration of each cable is slowly diminished before the vibration fully reaches the end compression 21. At the extreme outer ends of the original tube and of the resulting sleeve the edges 29 are rounded to present a neat finish to the end of the coupling; to reduce the cross section of the material at the extreme end and to defeat any tendency of the edge cutting into either the strands forming the conductor in the event that the coupling might assume an extremely sharp angle to either of the cables for any reason. When the connector or splicer tube is so formed. it is seen that the conductors as they leave its opposite ends, are free to move radially in any direction provided by the clearances 20. The cables as they tend to assume an angle relative to the connector for any reason .anele somewhat along the inclined surface at N and thus bend in inwardly spaced relation to the adjacent rounded edges 29 of the coupling.

The presence of the outer constriction 5 so close to the end of the tube will reduce and may even el minate the length of the clearance 20 except at its extreme outer end as indicated in Fig. 4. Assuming that the several compressions on the splicer tube are made with the same size die, then as above suggested, those which are in the extreme end areas of the tub are less severe-in their compression of the associated conductor than is the case of the two inner crimps 2 and 3 or 4. In this way gradual constriction of tube bore tends to cushion the cable conductors against the deleterious effects of vibration.

Stock tubes for forming electric connectors of the type herein disclosed are carefully designed and engineered at the factory with the intent that the crimps in the final connector should be of a definite length for each size of connector used and that for each size the spacing apart of each crimp and the relation of each to the ends of the conductor intruded therein and to the open ends of the connectors should be accurately set to obtain the maximum possible degree of advantages intended for each particular stock size. The mechanic installing the connectors is not always sure where the crimps are to be made in order to obtain these intended advantages. Further the installation is frequently made while the operator is hanging on to a cross arm or similar support high in the air with the conductors swinging back and forth particularly under storm conditions; at night, and otherwise under conditions not conducive to accurate setting of the parts and most times where the connection must be made quickly, in order to restore needed service.

The present disclosure features the use of means forming a prefixed indicator on the stock tube for assisting the operator in correctly locating the crimps even under such adverse circumstances. Briefly, the stock tube is manufactured at the factory .with some form of notice impelling indicators, sometimes called sight bands, on the outside of the stock tube and which sight bands can be set with more or less mathematic precision under carefully supervised'factory conditions exactly at the places where the crimps should be made. In Fig. 1 four of the necessary six such bandsare shown preferably stamped thereon in ink by suitable printing apparatus with adjustable and replaceable printing dies to meet varying requisites. In one form of the invention the bands were in the form of check marks, colored blue, on the aluminum background. The two innermost bands 30 and 3| preindicate by their several widths, the widths,

that is, the axial lengths, of the two inner crimps I and 2, and, by their spacing from the mid-plane 6-6, indicate where these inner crimps are to be made in order to properly space them relative to the inner ends of the conductors as previously located by the stops IT as the conductors. were forced into position.

The bands for indicating where the outer crimps are to be made are shown at 32 and 33 in Fi 1.

These initially printed bands on the stock tubes become permanently checked into the exposed surface of the finished connector as an incident of the crimping operation herein featured. As the checking is so slight no attempt has been made to show its depth in Fig. 1. It is suggested that these colored bands after they have thus formed their utility function may thereafter by reason of their notice impelling characteristics indicate origin of manufacture and thus possess trade mark value. Further they provide a convenient method in subsequent inspecting to determine whether the conductors have been properly installed. I

It is also suggested that the :bands 3033 be each provided on one side and at their midwidths with short thick arrows 34 which can function each as a tool centering indicator for locating the stock tube In accurately between the die jaws E--F of the crimping tool and in line with accurately located center marks provided on the sides of the jaws for this purpose.

With the cables in place and before any crimping thereon some suitable form of rust preventive filler is forced through the hole l8, into the center space or clearance 23 and into the interstices of the conductors following conventional practice in this respect. A plug 35 is driven into the hole to close the same and the tube crimped as herein featured.

Referring to the showing in Fig. '7, it will be seen that two connectors are used, one of relatively small dimension and housed within the other of larger dimension. The outer and larger connector 36 corresponding in general to the connector made from the stock tube III as hereinbefore described, except that its midlength portion 31 is longer than that shown at 26 in Fig. 3 in order to accommodate the inner and smaller connector 38; also two filler holes with plugs Mia and H81) are used and the center stops ll of the Figs. 1-4 form omitted.

It is intended that the cables A and B of Fig. 7 be connected by the longer connector 36 as has been herein described in detail in considering the disclosure in the proceeding figures.

In this case the ends of the conductive wire strands D of both of the cables A and B have been cut back to expose projecting end portions K and L of the center steel core C. These steel core end portions are intruded into the opposite open ends of the connector 38, corresponding as above noted except in size to the connector 36. The connector 38 is crimped on to the steel ends core end K and one crimp 40 at the core end L t is suflicient to make the connection, but it is, of course, obviously within the scope of the disclosure to use more than one crimp at each cable end as has been described for the outer connector 36. In forming the Fig. 7 disclosure the outer, and at that time uncrimped connector 36, is located loosely on one of the cables A or B, in position offset from the exposed ends K andL of the cables to clear both cable ends. The steel ends are then intruded into opposite ends of the inner connector 38 and the inner connector crimped on to the intruded steel ends K and L. The outer connector is then slid along the cable ends to bridge across the inner connector 38 and to enclose both ends of the cables. The outer connector 38 is then crimped into position a described for the Figs. 3 and 4 disclosure. In this way cables A and B are connected in two ways; first, by the outer sleeve 36 and also by the inner sleeve 38 coupling together the steel cores of the two cables. Referring to the disclosure of the dead-end connector shown in Figs. 8 and 9, it will be understood that the cables A and B are in this case connected electrically and mechanically through metallic connector M and are arranged to extend at an angle to each other as is known in similar forms of dead end connectors.

In Fig. 9 the cable B is not necessarily of the steel core type.

The connector M includes a T-shaped body portion N formed of two separable parts 0 and P including two overlapping plates secured together by bolts Q following conventional design in this respect. The part 0 includes initially a long open end tube R bifurcated at its right end to form a clevis, and. said bifurcated ends being slightly outset from the balance of the tube to form a pair of fiat parallel plates S, S as shown in Fig. 8.

The plates S and S are provided respectively adjacent their outer ends with transversely aligned bolt receiving apertures T and T.

The connector M also includes means for an- I choring the steel core C to the part 0. This means includes a separable part U, hereinafter referred to as an anchor, fitting into the clevis forming end of the tube R. Except that it is on a smaller size, it resembles the tube R and likewise comprises an open end to form a small clevis tube V bifurcated at its right end and said hifurcated ends being slightly offset from the balance of the tube to form a pair of flat parallel plates W and W. The plates W and W are provided respectively adjacent their outer ends with transversely aligned bolt receiving apertures T and T proportioned and arranged to align with the apertures T and T when the parts are in telescoped relation as shown in Fig. 9. The rounded corners or shoulders X between the tubular part V and its bifurcated legs W and W of the anchor are designed to fit in the curved corners or sockets Y provided therefor in the crotches found between tubular part R and it bifurcated legs S and S. The sockets Y act as stops for limiting the intrusion of the anchor into the tube R.

As shown in Fig. 8 the strands D are stripped back to expose an end K of the steel core C. The.

end of the cable A so stripped is drawn loosely through the uncrimped tube R to expose the core end K which is then introduced into the tube V. Tube V is then ci'imped on to the core end K with three crimps M as shown in Fig. 9. The cable A is then drawn from right to left from the position shown in Fig. 8 into the tube R until shoulders X on the anchor are seated in sockets Y of the tube R and at which time all the bolt holes T, T, '1 and T are in transverse alignment. Finally the left end of tube It is crimped on to the wire strands D with a pair of crimps 2| as shown at the left of Fig. 9. Tube R may be provided with a filler hole Z corresponding to the holes in which are fitted plugs 35, 18a and Nib.

In this way pull on the cable A to remove it from the support engaging in the aligned openings is resisted through its steel core by the engagement of the anchor U against the right end of the tubular part of the tube R.

The depending tube P has an end of cable B intruded into the same and crimped thereon with a pair of crimps 2| a herein before described in connection with the crimps formed in the preceding figures.

The dead-end connector with cables A and B thus attached thereto is secured to a suitable support (not shown) by means of a bolt or other fastening means passed through the aligned bolt holes T-T3.

Iclaim:

1. A dead end connector provided with means for mounting it in place and including an open end tube provided at one end with a stop, an anchor having a tubular part intruded into one end of the tube and having a part abutting'zthe stop, to limit its intrusion, a cable having an end thereof intruded into the other end of the tube and with an end of its steel core extending therefrom to form an exposed core end, said core end intruded into the tubular part of the anchor and said tubular part of the anchor being crimped onto the exposed core end, and said tube being crimped onto the part of the cable contained therein.

2. A stock tube for forming a coupling sleeve fashioned to be distorted into a binding engagement with conductors intruded into the opposite ends thereof, said tube provided with a bore the central portion or which is of uniform section and serrated, the end portion of the bore being of slightly greater diameter than the central portion and the portion of the bore between the central portion and each end portion forming intermediate tapered portions and each end of the tube gradually increasing in diameter from the smaller diameter central portion towards the relatively larger diameter portions, the intermediate and end portions of the bore being smooth and thus not serrated, and which is provided adjacent its mid-length with a transversely extending hole opening into the bore.

3. In a device of the class described, the combination of a malleable metal tube and the end of a cylindrical conductor of the steel core and metal strand type intruded into one end of the tube, said tube being exteriorly crimped in an area adjacent to but spaced slightly from the end of the conductor to deform the bore of the tubeand the portion of the conductor therein into a binding interiit with a transverse plane of greatest constriction, andin which plane the area of the cross section of the conductor is approximately the aggregate cross sectional area of the metal strands and the steel core, the bore and the portion of the conductor therein gradually increasing in cross-sectional area in both axial directions from said plane of greatest constriction to form a waist-like, double-conical, hour- 12 glass form of interflt between the conductor and tube, the conductor at the ends of said double conical form being distended and having its strands more separated than at the plane of greatest constriction and also having its strands more separated than in the initial conductor, thus providing a conductor having cross-sections slightly greater than the cross section of the conductor in its initial undei'ormed portion as the same is measured at a point externally oi the tube.

4. In a device 01' the class described, the combination of a coupling sleeve of malleable metal and a cylindrical conductor of the strand type inserted into one end of the sleeve with a sliding tit and capable oi! being either compressed or distended radially from its initial cross sectional area, said sleeve being crimped on to the conductor at a plurality of spaced apart points to form succeeding lengths of crimped and uncrimped areas, the sleeve at its uncrimped areas being circular and relatively large in cross section, the sleeve in its crimped areas being hexagonal and relatively small in cross section, the bore of the sleeve being circular in cross section at all points in its length which contains the conductor, the bore and the conductor therein being of undulatory form and in snug interfitting relation, the conductor defining a plurality of waist-like, conical wedging keys for resisting relative axial movement between conductor and the sleeve, each key being of greater length than its associated crimped area and substantially centered therein and whose enlarged ends are located mid-length of the next adjacent uncrimped areas and distending radially into the same, each key having mid-length thereof a cross section of least area and of maximum density and at its ends having its greatest cross section and its least density.

5. In a device of the class described, the combination of a pair of conductors each of the stranded type, circular in cross section and capable of being contracted or distended from their original cross sectional area and a metallic sleeve whose bore is circular in cross section at every point along its length and of variable diameter and into the opposite ends of which bore the conductors are intruded with a sliding fit, said sleeve provided at its mid-length with stop means projecting into the bore of the sleeve for limiting the intrusion of the conductors into the bore and the space between the adjacent ends of the conductors forming a gap space, each end of the sleeve outwardly of said gap space forming crimpable ends, each provided in spaced relation to its ends with at least two longitudinally spaced-apart crimped areas each having its least cross sectional area of its bore approximately centered within its associated crimped area and the part of the conductor within each crimped area gradually increasing in cross section in both axial directions thereby to form the bore and the part of the conductor therein as a series of double conical forms, the bore being of maximum diameter at the mid-length gap space and into which space the adjacent ends of the conductors are distended to form innermost wedging keys, and the maximum diameter of each double conical form considered outwardly away from the gap space being of less diameter than the end which distends into the gap space.

MARTIN D. BERGAN.

(References on following page) 13 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Bennett May 13, 1884 Fleming Oct. 27, 1891 Rosati Aug. 12, 1902 Dibner June 12, 1928 Webber Aug. 7, 1928 Cooper May 7, 1929 Wills May 14, 1929 Varney Feb. 17, 1931 Brenizer Apr. 28. 1936 Vietzen Oct. 27, 1936 Smith Dec. 21, 1937 Cook Aug. 9, 1938 Dickie et a1 Feb. 28. 1939 Number Number Name Date Jensen Mar. 21, 1939 Heath Feb. 6, 1949 Dixon Mar. 12, 1940 Eby Aug. 6, 1940 Klein June 3, 1941 Temple July 1, 1941 Jensen July 29, 1941 Klein Aug. 5, 1941 Burns Sept. 2, 1941 Hayford Dec. 15, 1942 Burns Feb. 29, 1944 Dibner May 8, 1945 FOREIGN PATENTS Country Date Great Britain May 22, 1936 Germany Oct. 26, 1939 

